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  Yamaha: Tilt Trim Cylinder Leaks Down

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Author Topic:   Yamaha: Tilt Trim Cylinder Leaks Down
jimh posted 07-08-2002 12:57 PM ET (US)   Profile for jimh   Send Email to jimh  
On my 1987 Yamaha 70-HP engine, the engine tilt and trim cylinder will slowly leak down, ultimately letting the engine lower to the fully down position.

I think the hydraulic cylinders are okay, because they have no problem lifting the engine. The trim cylinders will raise the engine even against the full thrust of the engine at wide-open-throttle.

My guess is that there must be a check valve in the hydraulic pump which is letting the line pressure bleed off.

--Does this sound like a good diagnosis?
--Has anyone had the same problem with their Yamaha engine of this vintage?
--Does anyone have a repair bill from such a repair? How much? Can you do it yourself?

Another thought is perhaps the system is low on fluid. I have not opened the resevoir to check because I do not know what kind of fluid to add. My only reference for this is an aftermarket repair manual that instructs to add "Yamaha Hydraulic Fluid".

--Would low fluid show this symptom?
--What is an aftermarket source of hydraulic fluid? [I don't really think it is necessary to ship hydraulic fluid from Tokyo to fill this resevoir, even if it has a metric screw on the cover. ;-) ]

Bigshot posted 07-08-2002 02:21 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Jim it has a check valve and that is most likely your problem unless you see a leak. The big nut is where you fill it and I believe on yamaha's it is 10-30 oil....not ATF like OMC. The check valve is about $5 but unfortunately you have to remove engine to fix it. Mine was the same way and I just moved my tilt pin up and called it a day. When you get time it is not that hard to hang the engine and fix it. If you gonna do so....consider changing the pump motor if all rusty like most older Yams.
whaleryo posted 07-08-2002 02:40 PM ET (US)     Profile for whaleryo  Send Email to whaleryo     
Jim,

I have the same engine and in my case the seals need replacing. With the engine up, if I apply downward pressure, I'll see a small amount of fluid seeping past a seal on one of the trim rods. Estimated parts and labor $250.

If your fluid is low (Yamalube Tilt/Trim fluid about $3.00/tube) there is a bleeding ritual that just might fix your problem. Let me know if you need the details - I have the manual.

Bill

Bigshot posted 07-08-2002 02:45 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
They should be self bleeding.

When fuid gets low it usually will not lift the engine. When it lifts it uses like 600psi, when lowering it is like 250. For it to leak down and then just lift it back up without any air in the system....check valve.

whaleryo posted 07-08-2002 02:57 PM ET (US)     Profile for whaleryo  Send Email to whaleryo     
Makes sense about the check valve being the suspect. There definately is a procedure for bleeding on this particular engine however, I've had to do it several times.
Doug Weaver posted 01-07-2003 05:57 PM ET (US)     Profile for Doug Weaver  Send Email to Doug Weaver     
I just noticed that the tilt/trim is not working on the 1989 225-hp Yamaha engine on my Whaler. Jim, my engine does the same thing you described by creeping slowly down from the full up position. Lately I have noticed a sound when I activate the tilt button that sounds a bit like air in the system, but not too sure. Did you ever figure out what was wrong with your tilt/trim? The pump activates and makes noise, but the engine does not move up or down. I sense $$$. Any suggestions/experiences out there?
Clark Roberts posted 01-08-2003 07:47 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Try adding an oz or so of "automatic transmission conditioning fluid". This will swell the seals and "O-rings" a bit and may solve your problem. It's like chicken soup..."can't hurt"! The stuff is available at auto supply stores under several brand names. This has worked for me on several Yamahas. Go for it!.. Happy Whalin'.. Clark. Spruce Creek Navy
Doug Weaver posted 01-08-2003 08:12 PM ET (US)     Profile for Doug Weaver  Send Email to Doug Weaver     
Thanks for the idea. I went out today and the damn thing is working again, but did notice that the pin located at the top of the main hydraulic seemed to be a little sticky. Not too sure how to verify the proper fluid level in this trim reservoir. Maybe that is the whole problem, since I've been hearing an air type sound when activating the trim. Do I fill the reservoir to the level of the large access bolt on the reservoir like you would a manual transmission? Other than the described problem, there are no leaks that I can find. Thanks for the help.
lpaton posted 01-09-2003 06:55 AM ET (US)     Profile for lpaton  Send Email to lpaton     
My 200 hp Yamaha started doing the same thing "after" a full trim tilt rebuild. There is a bypass valve which is opened by a screw on the side and used to manually raise/lower the engine whwn the battery is dead. I opened this valve and ran the tilt for a minite or two recirculating the oil . Fixed the problem. Must have been dirt somewhere.
Laird
hauptjm posted 01-09-2003 10:32 AM ET (US)     Profile for hauptjm    
Most modern T/T systems are self-bleeding. The most common occurance of failure seems to be the check valve and the accompanying seal that closes the system. Obviously, air is your worst enemey. I had the same exact syptoms last summer and changed the check valve and it works like a charm.
Doug Weaver posted 01-09-2003 12:35 PM ET (US)     Profile for Doug Weaver  Send Email to Doug Weaver     
Thanks for the info. I will try those ideas and see what happens.
lhg posted 01-09-2003 03:12 PM ET (US)     Profile for lhg    
I have found the repair for the problem JimH is talking about to be expensive to fix. On a Merc, it's about a $750 job.
j_h_nimrod posted 01-09-2003 10:58 PM ET (US)     Profile for j_h_nimrod  Send Email to j_h_nimrod     
You might want to open the manual release like lpaton suggested and when you finish retighten then loosen the release screw a couple times. Finally, completly retighten the screw and test it. Sometimes, yet rarely, this screw looses its complete seal and develops a very slight leak.

More ramblings.

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